Ignition apparatus



Aug. 20, 1968 R. PHLUPS 3,397,683

IGNITION APPARATUS Filed Feb. 25, 1966 3 Sheets-Sheet 2 l 3 INVENTOR. E0jiPH/ZU/ZS B JM A TTO United States Patent C "ice 3,397,683 IGNITIONAPPARATUS Roy Phillips, R0. Box 1716, Ormond Beach, Fla. 32074 FiledFeb. 25, 1966, Ser. No. 530,183 8 Claims. (Cl. 123-148) ABSTRACT OF THEDISCLOSURE An ignition system for an internal combustion engineincluding a distributor having at least one contact flush with a smoothannular internal surface thereof adapted to be electrically connectedwith a spark plug of the engine, a rotatable generator assembly having asmooth surface in sliding engagement with the annular surface of thedistributor and provided with a flush contact which momentarily engagesthe contact carried by the distributor upon rotation of the generatorassembly, piezoelectric elements carried by the generator assembly andelectrically connected to the contact of the generator assembly, andmeans for periodically and simultaneously squeezing and relaxing thepiezoelectric elements in timed relation to rotation of the engine.

The present invention relates to ignition systems for internalcombustion engines the air-fuel mixture of which is ignited by anelectric spark and more particularly to ignition systems for internalcombustion engines of the character referred to, preferably of themulti-cylinder type, which ignition systems include piezoelectric meansfor developing the electrical potential used to produce the spark whichignites the air-fuel mixture in the cylinder or cylinders of the engine.

One of the principal objects of the invention is the provision of a newand improved ignition system for internal combustion engines, preferablyof the multicylinder types, which utilize an electric spark to ignite anair-fuel mixture in the cylinder or cylinders of the engine, whichsystem includes a piezoelectric element for providing the electricalpotential required to produce the desired spark or sparks, means forcausing the piezoelectric element to produce the required potential, andmeans for conducting the potential to the spark plug or plugs of theengine at the desired time and with a minimum loss of potential.

Another object of the invention is the provision of a new and improvedignition system for internal combustion engines, preferably of themulti-cylinder type, which utilize an electric spark for igniting anair-fuel mixture in the cylinder or cylinders of the engine, whichsystem includes a piezoelectric element for providing the electricalpotential required to produce the desired spark or sparks, means forcausing the piezoelectric element to produce the required potential inadvance of the time it is to be utilized, and means for subsequentlyconducting the potential to the spark plug or plugs of the engine at thedesired time.

Another object of the invention is the provision of a new and improvedignition system for internal combustion engines, preferably of themulti-cylinder type, which utilize an electric spark for igniting anair-fuel mixture in the cylinder or cylinders, which system includes apiezoelectric element for providing the electrical potential required toproduce the desired spark or sparks, means for causing the piezoelectricelement to produce the required potential in advance of the time it isto be utilized, and means for subsequently conducting the potential tothe spark plug or plugs of the engine at the desired time, whichlast-mentioned means includes means for establish- 3,397,683 PatentedAug. 20, 1968 ing direct contact between relatively movable conductingmembers and preventing the conduction of the potential to the spark plugor plugs of the engine until the direct contact between the relativelymovable conducting members is made.

Another object of the invention is the provision of a new and improvedignition system for internal combustion engines, preferably of themulti-cylinder type, which utilize an electric spark for igniting anair-fuel mixture in the cylinder or cylinders of the engine, whichsystem includes a piezoelectric element for providing the electricalpotential required to produce the desired spark or sparks in combinationwith means for causing the piezoelectric element to produce the requiredpotential in advance of the time it is to be utilized, means forsubsequently conducting the potential to the spark plug or plugs of theengine including relatively movable conducting members adapted to make adirect engagement with one another to conduct the potential to the sparkplug or plugs of the engine, and means for varying the time ofestablishing the direct engagement between the relatively movableconducting members as a function of the rotational speed of the engine.

Another object of the invention is the provision of a new and improvedignition system for internal combustion engines, preferably of themulti-cylinder type, which utilize an electric spark for igniting anair-fuel mixture in the cylinder or cylinders of the engine, whichsystem includes a piezoelectric element carried by a member adapted tobe rotated in timed relation to the rotation of the engine for providingthe electrical potential required to produce the desired spark orsparks, means for causing the piezoelectric element to produce therequired potential in advance of the time it is to be utilized, meansfor subsequently conducting the potential to the spark plug or plugs ofthe engine including conducting members movable relative to one anotheradapted to make direct engagement with one another to conduct thepotential to the spark plug or plugs of the engine, and fluid couplingmeans between the conducting members for varying the time ofestablishing the direct engagement between the relatively movableconducting members as a function of the rotational speed of the engine.

Another object of the invention is the provision of a new and improvedignition system for internal combustion engines of the characterreferred to, which system includes a piezoelectric element carried by amember adapted to be rotated in timed relation to the rotation of theengine, means movable against at least one end of the piezoelectricelement for alternately compressing and relaxing the element causing theelement to produce the required electrical potential, and means forconducting the potential to the spark plug or plugs of the engine.

Another object of the invention is the provision of a new and improvedignition system for internal combustion engines of the characterreferred to, which system includes a piezoelectric element carried by amember adapted to be rotated in timed relation to the rotation of theengine within a housing having an interior cam surface or track thereon,lever means operable against at least one end of the piezoelectricelement, roller means carried by the lever means and engageable With thecam surfaces or track on the housing for alternately compressing andrelaxing the element to cause the element to produce the requiredelectrical potential, and means for conducting the potential to thespark plug or plugs of the engine.

Further objects and advantages of the invention will be apparent tothose skilled in the art to which it relates from the following detaileddescription of two preferred embodiments thereof made with reference tothe accompanying drawings forming a part of the specification and FIG. 3is a sectional view taken approximately at line 3-3 of FIG. 1;

FIG. 4 is a sectional view taken approximately at line .4-4 of FIG. 1;

FIG. 5 is a sectional view taken approximately at line 55 of FIG. 1;

FIG. 6 is a sectional view taken approximately at line 66 of FIG. 5, ofa portion of a second ignition system embodying the present invention;and

FIG. 7 is a sectional view taken approximately at line 7-7 of FIG. 6.

The present invention relates to an improved ignition system for aninternal combustion engine, preferably of the multi-cylinder type,having a spark plug or plugs for igniting the fuel mixture in thecylinder or cylinders of the engine. The ignition system, generallyspeaking, includes a spark generating means including a piezoelectricunit, and distribution means for connecting the piezoelectric unit tothe spark plug or plugs of the engine to ignite a fuel-air mixture inthe combustion chamber or chambers thereof at the proper time in thecycle of operation of the engine.

In the preferred embodiments of the invention shown, the piezoelectricunit is a part of an assembly rotatable within a stationary housing andis alternatively compressed and relaxed upon rotation of the assembly toproduce the desired electrical potential by at least one lever rotatablewithin the housing with the piezoelectric means and provided with aroller which traverses a cam track on the interior of the housing havingradially high and radially low portions. The potential is produced inadvance of the time in the cycle of operation of the engine when it isto be used and is directly conducted to the spark plug or plugs at theproper time without the intervention of an air gap and with minimum lossof potential. Provision is also made automatically advancing orretarding the time when the potential is delivered to the spark plug orplugs as a function of the rotational speed of the engine crankshaft. Asshown, this is accomplished by a distribution member operativelyconnected to the rotatable assembly which carries the piezoelectric unitby means including a fluid coupling which permits the distributionmember to move angularly relative to the rotatable assembly carrying thepiezoelectric unit as a function of the speed of the engine.

Referring to the drawing, the ignition system shown in FIGS. 1 to 5 ofthe drawings comprises a two-part housing member, designated generallyby the reference character A, adapted to be fixedly secured to astationary part of the engine with which the system is used, forexample, the engine block B. The lower part 10 of the housing A is shownas formed of various metal and/or plastic members welded or otherwiseconnected to one another, although it could be molded as a singleplastic part. The upper or cover part 11 of the housing A is preferablya plastic molded member.

The housing A contains a first or potential generating assembly C whichincludes a piezoelectric element or unit D for producing the electricalpotential and which assembly is fixed to the upper end of a shaft 12rotated in timed relation to the rotation of the crank shaft of theengine to alternately compress and relax the piezopart or cover 11 ofthe housing A to advance or retard the spark as will be hereafterdescribed.

The input or driving shaft 12 is journaled in the lower portion or part10 of the housing A and carries at its upper end the generator assemblyC comprising a flanged base member 20 pinned to the shaft 12 and whichmember 20 in turn carries a member 21 fixed to its upper side by screws22 and 23 and which member houses two spaced, axially alignedpiezoelectric elements 24 and 25.

The piezoelectric elements are adapted to be alternately squeezed orcompressed in the direction toward one another and released or relaxedby a pair of levers 2'6 and 27. The levers 26 and 27 are fulcrumedadjacent to one of their ends about cylindrical members 28 and 29,respectively, which are supported by abutment members 30 and 31 carriedby the base member 20. Opposite ends of the levers 26 and 27 carryrollers 32 and 33 which travel about a cam track or surface 35 on theinterior of the lower member 10 of the stationary housing A. The camtrack has alternately radially high and low portions 40 to 47. Thecrests of the radially high portions 40, 42, 44 and 46' and the valleysof the low portions 41, 43, and 47 are arcuate in shape and are ofconsiderable length. As shown each crest of the high portions andthebottoms of eachvalley extend through an arc of about 40.

As the first or generating assembly C rotates, the levers 26 and 27simultaneously compress the piezoelectric elements 24 and 25 throughmembers 50 and 51 interposed between the ends of the piezoelectric units24 and 25 and the levers 26 and 27, respectively, as the rollers 32 and33 ascend and travel along oppositely disposed high portions of the camtrack 35. The levers 26, 27 allow the piezoelectric elements to relax asthe rollers enter and travel along oppositely disposed radially lowportions of the cam track. Since there are four crests and four valleysin the cam track 35 the piezoelectric units are compressed and allowedto relax four times for each rotation of the generator assembly C thusproducing eight potentials or potential periods.

The ends of the piezoelectric units 24 and 25 adjacent to one anotherabut or engage movable members and 61 within the member 21. The sides ofthe members 60 and 61 facing one another are inclined to produce aV-like space therebetween and a wedge member 63 is interposedtherebetween. The wedge member 63 is biased by a spring 64 in adirection to force it between the members 60 and 61 to automaticallytake up any slack or looseness in the mechanism. The spring 64 isinterposed between the member 63 and a contact member 65 having aspherical lower end contacted by the spring 64. The piezoelectricelements 24 and 25, the members 50, 51, '60, 61, 63 and 64, and thelower end of the contact member 65 are located in suitable apertures inthe member 21.

The contact member 65 is molded into the member 21 and extends upwardlythrough a boss 66 on the upper side of the member 21 which boss extendsinto an aperture opening into the underside of a ring-like member 70.The members 21 and 70 are made of plastic insulating material. The boss'66 projects through an aperture in a plate 71 interposed between themember 21 and the member 70. The boss 66 fits in the apertures in themembers 70 and 71 without looseness or play thus causing the members torotate with the member 21 as a part of the first or generator assemblyC.

The upper end of the member 65 is enlarged and forms a short ar'cuatecontact member 72 which terminates in the plane of a smooth annularupper surface 73 of the member 70. The surface 73 engages a smoothannular lower surface 74 of the member 13 of the distributor assembly Eand rotates relative thereto.

The member 13 of the distributor assembly E, which is made of plasticinsulating material, includes an upwardly projecting ring-like boss 75and has a plurality of annularly spaced-apart openings 76 therein withinwhich contact assemblies 77 to 84 are positioned. Each of the contactassemblies 77 to 84 includes a sleeve member 87 located in the uppercounterbored ends of the apertures 76 and a pair of spaced contactmembers 88 and 89. The contact members 88 and 89 of each assembly areslidably disposed in their respective sleeve members 87 and the lowerends of the apertures 76 and are biased oppositely, that is, in adirection away from one another by a spring 90 interposed therebetween.The contact members 88 are biased downwardly by the springs 90 and intocontact with the upwardly facing surface 73 of the member 70 and theupper surface of the contact member 72 which surface is flush with thesurface 73. The contact members 89 are urged or biased by the spring 90in an upwardly direction and into engagement with a downwardly facingannular surface 91 in the interior of the cover member 11 of thedistributor assembly E.

The contact member 72 in the first or generator assembly C sequentiallyand momentarily engages the contact members '88 in the member 13- of thedistributor assembly E as the generating assembly C is rotated. Thepotential developed by the generator assembly is transmitted from thecontact member 72 to a contact member 88 in the distributor assemblyonly during engagement of the contact member 72 with the member 88because the surfaces 73 and 74 closely engage one another and withoutany air gap therebetween and because the plastic material of the members70 and 13 are of such dielectric strength that arcing between thecontact 72 and the contacts 88 is prevented as the contact 72 approachesindividual ones of the contact members 88. Since the surfaces 73, 74 arein engagement with each other there is no air gap between approachingcontacts and arcing between approaching contacts which would result inpreignition is prevented. The potential delivered to the contacts 88 istransmitted to the contacts 89 through the spring 90 and sleeve 87.

The one end of the conductors 92 to 99 extending between the distributorassembly E and the spark plugs of the engine terminate in or areconnected to arcuatelyshaped contact members 101 to 109, respectively,equally spaced about and having the lower surfaces flush with theannular surface 91 within the cover member 11 of the housing A. Thecontact members 89 are urged by the spring 90 into engagement with thesurface 91 and the undersides of the contact members 101 to 108 with theresult the electric potential is conducted from a contact member 89directly to the particular spark plug with which it is associated.

The member 13 which carries the contact assemblies 79 is oscillatablerelative to the potential generator assembly C and the cover 11 of thehousing A by the action of a fluid coupling P so that the contactassemblies 79 may be moved angularly relative to the potential generatorassembly to automatically vary the spark timing as a function of thespeed of the engine. The fluid coupling F comprises a disk or plate-likemember 120 carried by a shaft 121 the lower end of which rests upon themember 71 of the potential generator assembly and is rotatably supportedby needle bearing 122 in a member 124 secured to the top of the plate 71of the potential generator assembly C by a plurality of screws 124, onlyone of which is shown in the drawings. The member 124 includes a centralcylindrical aperture therein for receiving an end of the output shaft121 and the needle bearings 122 which rotatably support the shaft. Themember 124 includes a peripheral, stepped, upstanding flange 126 at anupper side within the upper end of which is fixed an apertured plate 127forming a viscous shear fluid chamber 128 in the member 124. Thewheel-like plate 120 fixed to the shaft 122 is positioned in a viscousshear fluid contained in the chamber 128. The upper and lower surfacesof the fluid coupling member lie closely adjacent upper and lower wallsof the chamber 128. An annular plate-like member 131 is supported on theflange 126 and is spaced from the member 127 to form a chambertherebetween which is effective to prevent loss of the fluid from thegenerator assembly C. An upper surface of the member 131 is co-extensivewith the planar surface 73 of the member 70. The output shaft 120extends through apertures in members 127, 131, 13 and through an opening132 in the cover 11.

The output shaft 121 of the fluid coupling is rotatable relative to thecove-r 11 in response to viscous shear forces acting on the couplingmember 120. Rotation of the output shaft 121 relative to the housing 11in a clockwise direction as viewed in FIG. 2 is resisted by a spiralspring 133 surrounding the upper end of the output shaft 120 and havingits inner end bent downwardly to engage a pin 135 extending radiallyfrom the upper end of the output shaft 121. The opposite or outer end136 of the spring 133 is adapted to engage with one of a plurality ofpins 140 143 equally spaced from one another on the cover member 11 andextending upwardly therefrom. The spring 133 biases the output shaft 121in a counterclockwise direction and rotation of the output shaft 121 dueto the bias of spring 133 is limited by engagement of the pin 135 withthe pin member 143.

At a predetermined speed of rotation of the generator assembly C, torquetransmitted through the fluid coupling F is sufficient to overcome thebias of the spring 133 and the output shaft 121 is rotated against thebias of the spring in a clockwise direction.

Rotation of the output shaft 121 rotates a gear 144 secured as by a pinto the output shaft 120 in a clockwise direction which in turn rotates agear 146 meshed therewith in a counterclockwise direction The gear 146is rotatably supported by a headed shaft-like member 148 which ismounted in the cover 11 and which supports the pin 140. The gear 146meshes with a ring gear 147 fixedly secured to the member 13.counterclockwise rotation of the gear 146 causes counterclockwiserotation of the ring gear 147 which results in rotation of the member 13in a counterclockwise direction. Rotation of the member 13 in acounterclockwise direction moves the contact members 88 relative to thehousing A and the generator assembly, to a position where they arecontacted by the contact 72 earlier in the cycle of the engine toadvance the spark.

The amount of spark advance may be adjusted by adjusting the tension inthe spring 133. The end 136 of the spring 133 may be engaged with any ofthe pin members 140 through 143 to effect this adjustment. The cover 11of the housing A includes an upstanding flange which surrounds theoutput shaft 121 and pin members 140 through 143. The flange 150supports a cap member 151 which snugly engages the flange 150 to protectthe spark advance mechanism and which is removable to permit access tothe spring 133 for adjustment purposes. This adjustment of the sparkadvance is particularly use ful in matching the spark timing to octanerating of a particular fuel used in the engine.

The end portions of the conductors 92 to 99, as previously mentioned,are enlarged and form circumferentially extending arcuate contactsurfaces for the transmission of an electric potential between thecontact members 89 and each of the conductors. This configuration of theends of the conductors 92 and 99 permit the member 13 to be rotatedrelative to the housing to advance the spark while maintainingelectrical contact between the contacts 89 and their respectiveconductors.

In order that the engine may be stopped when desired, means is providedfor diverting the spark from the spark plug to ground, and therebypreventing ignition. As shown in the drawings, the means for preventingignition includes a housing 149 secured to the lower portion 10 of thehousing A and surrounds a solenoid coil 150. The solenoid coil 150 isoperable on actuation of a switch, not

shown, to move a headed shorting pin 151 into and out of engagement withan annular shorting ring 152 surrounding the potential generatingassembly C. The shorting ring 152 is positioned on an inner periphery ofthe cover 11 of the housing A and closely adjacent a shorting conductor153 connected to the conductor 65 in the generator assembly C. It willbe apparent that as the generator assembly C rotates, the shortingconductor 153 rotates therewith in close proximity to the shorting ring152. The lower end of the shorting pin 151 is connected to an anmaturemember 154 reciprocable in the solenoid coil 150 upon energizati-on ofthe solenoid. The armature 154 includes an enlarged flange portion 155which limits movement of the armature in both directions by engagernentwith portions of the housing 149. The upper end of the pin 151 carriesan annular body of insulating material 156 fixed between an abutment 157on the pin and the head thereof. When the ignition switch is turned onand the solenoid is actuated the armature 154 and the parts connectedthereto including the shorting pin 151 are moved upwardly against thebias of a compression spring 158-interposed between the head of the pin151 and the bottom of a recess or aperture 159 in the cover 11 andwithin which the upper end of the pin 151 is slidably supported to theposition shown in the drawings. With the parts in this position theinsulating material 156 prevents conduction between the shorting ring152 and ground. When the ignition switch is turned off the solenoid 150is de-energized and the anmature 154 moves down under the force ofgravity and the spring 158 to a point where the flange 155 engages thebottom portion of the housing 149. At this position, the head of theshorting pin 151 contacts the portion of the shorting ring 158 extendingto the aperture 159. When the shorting pin 151 and the shorting ring 152contact, the potential developed in the generator assembly C isconducted through the shorting conductor 148 and arcs to the shortingring 152. The potential is conducted from the shorting ring 152 throughthe shorting pin 151, armature 154 and housing 149 to ground.

FIGS. 6 and 7 disclose a modified ignition system embodying the presentinvention and wherein parts, which are duplicates of those shown inFIGS. 1 to 5, are designated by the same character references, but withprime marks attached thereto. The only changes in the ignition systemshown in FIGS. 6 and 7 over the system shown in FIGS. 1 to are in thepotential generating assembly and the contour of the cam surfaces withinthe bottom part of the housing and only those parts will be described indetail.

In the modified embodiment the potential assembly I includes a baseplate 171 positioned above and welded to a smaller plate 172 rigidlyconnected to the upper end of the input or drive shaft 12' connected forrotation with the crank shaft of the motor as previously discussed. Inthe embodiment being described, the plate 71 is connected to and spacedfrom the plate 171 by a tubular sleeve 173 surrounding rivets 174extending through the plates 71 and 171. The piezoelectric unit K isfixedly secured be tween the plates 71 and 171 and has a downwardlyextending portion 174 which fits within an aperture 175 in the plate171.

The piezoelectric element is adapted to be alternately compressed andrelaxed by a lever 176 which is also carried by the base plate 171. Thelever 176 is fulcrumed adjacent one of its ends about a cylindricalmember 177 carried by the base plate 171 and supported by an abutmentmember 178. The opposite end of the lever 176 carries a roller 180 whichtravels about a cam track 181 forming an inner peripheral surface of alower portion or member 182 of the stationary housing H. The cam track181 includes radially high and low portions 183-190 along which theroller 180 is moved as the generator assembly I rotates. The radiallyhigh and low portions 183491 are arcuate in shape and are ofconsiderable length. The crests and valleys of the radially high and lowportions form dwell portions on the cam track 181 which extend throughan arc of about 40 degrees.

As the generator assembly I rotates the lever 176 is ro tated slightlyabout the pivot pin 177 as a result of engage meut between the rollerand the cam track 181, to compress and relax the piezoelectric elementK. The lever 176 acts on the piezoelectric element K through a mem her193 interposed between the end of the piezoelectric element and aportion of the lever 176 intermediate the roller 180 and pivot pin 177.The piezoelectric element is compressed as the roller ascends andtravels along the crest of the radially high portions 184, 186, 188,190, and is allowed to relax as the roller travels along the radiallylow portions 183, 185, 187, 189 of the cam track 182. Since there arefour crests and four low portions on the cam track 182 the piezoelectricelement will be compressed and relaxed four times during one revolutionof the generator assembly I to potential periods.

The end of the piezoelectric element K opposite the end engaged by themember 193, engages a block "194 which is supported against movement bya wedge member 195 interposed therebetween and one of the spacer sleeves173. The wedge member 195 is associated with a spiral spring 196supported on the base plate 171 and which urges the wedge member 195between the fixed abutment 173 and the block 194. The wedge member 195compensates for shrinkage, etc. of the piezoelectric unit.

As the generator assembly I rotates, the potential developed by thepiezoelectric element K is conducted from the unit through a conductormember 198 to a contact member 199 terminating in the annular rotatableupper surface 73' of the member 70 of the generator assembly I. As thegenerator assembly rotates in the housing H, the potential developed inthe piezoelectric element is delivered from the contact member 199sequentially to the contacts 88' in the distributor assembly E fromwhich the potential will be conducted to individual ones of the sparkplugs of the engine.

The operation of the ignition device illustrated in FIGS. 6 and 7 issubstantially the same as that illustrated in FIGS. 1-5 and will not bedescribed as its operation can be understood from a consideration of thedescription of the operation of the ignition system shown in FIGS. 1-5.

From the foregoing description of the preferred embodiments of theinvention, it will be apparent that the objects hereinbefore enumeratedand others have been accomplished and that there has been provided anovel and proved ignition system for an internal combustion engine.Because of the sliding contact feature of the present invention whicheliminates air gaps and the use of a piezoelectric element to producethe required high potential as described, at no time are there any highvoltage circuits or conducting ionized conducting paths interrupted orbroken. The voltage or potential generated in the piezoelectric elementis discharged through the spark plug or plugs of the engine anddissipated before the circuit is broken. The absence of an air gap inthe sliding contact area prevents any premature ionization and arcingprior to the meeting of the contacts thus providing sharp accuratetiming of the high voltage discharge.

While the preferred embodiments of the present invention have beendescribed in considerable detail the invention is not to be consideredlimited to the precise construction shown. My intention is to herebycover all adaptations, modifications and uses of the ignitionshown whichcome Within the practice of those skilled in the art to which theinvention relates and within the scope of the appended claims.

What I claim is:

1. An ignition system for an internal combustion engine including ahousing, a distributor assembly contained in said housing and having atleast one contact adapted to be electrically connected with a spark plugof the engine,

produce eight potentials orsaid distributor assembly having a smoothannular internal surface and said contact being substantially flushtherewith, a generator assembly rotatably supported in said housing andhaving a smooth surface in sliding engagement with said annular surfaceof said distributor assembly, said generator assembly having a contactwhich is substantially flush with said smooth surface thereon and whichmomentarily engages the contact carried by said distributor assemblyupon rotation of said generator assembly, means adapted to operativelyconnect said generator assembly with said engine for rotation of saidgenerator assembly in timed relation to rotation of the engine, firstand second piezoelectric elements carried by one of said assemblies andelectrically connected to the contact of said generator assembly, andcooperable means carried by said generator assembly and said housing forperiodically and simultaneously squeezing and relaxing saidpiezoelectric elements in timed relation to rotation of the engine tocause the piezoelectric elements to periodically generate electricpotentials.

2. The ignition system defined by claim 1 wherein said piezoelectricelements are aligned on said generator assembly, and said cooperablemeans include first and second lever members operatively associated withends of said piezoelectric elements and which are operable in responseto rotation of said generator assembly to move simultaneously inopposite directions toward and away from said piezoelectric elements tosqueeze and relax said piezoelectric elements in timed relation torotation of the engine.

3. The ignition system defined by claim 2 wherein said piezoelectricelements are separated by means for supporting said piezoelectricelements and resisting movement of said elements in response to movementof said lever means, said support means including a wedge member movablein response to a change in dimension in said piezoelectric elements tocompensate for shrinkage of said piezoelectric elements.

4. The ignition system defined by claim 1 wherein said cooperable meansincludes first and second lever members mounted on said generatorassembly for rotation therewith and a cam track forming an innerperiphery of said housing and wherein said cam track and said first andsecond lever members are cooperable to cause rotation of said levermembers relative to said generator assembly upon rotation of saidgenerator assembly, each of said lever means being pivotally supportedon said generator assembly and including a portion intermediate endsthereof for applying a compressive force to an associated piezoelectricelement in response to rotation of said lever member in one directionand for relaxing said piezoelectric element in response to rotation ofsaid lever member in an opposite direction.

'5. An ignition system for an internal combustion engine including ahousing, a distributor assembly rotatably supported in said housing andincluding at least one contact adapted to be electrically connected witha spark plug of the engine, said generator assembly having a contactwhich is substantially flush with the smooth surface thereon and whichsequentially engages the contact carried by said distributor assemblyupon rotation of said generator assembly, piezoelectric means carried byone of said assemblies and electrically connected to the contact of saidrotatable generator assembly, means for compressing and relaxing saidpiezoelectric elements in timed relation to rotation of the engine tocause said piezoelectric element to periodically generate electricpotentials, and spark advance means operatively associated with saidgenerator assembly and said distributor assembly for moving saiddistributor assembly relative to said generator assembly and saidhousing in response to rotational speed of said generator assembly, saidspark advance means comprising a fluid coupling including a chamberformed in said generator assembly, a viscous shear fluid in said chamberand an output coupling member in said chamber having a surface adjacentto a wall of said chamber and being operatively connected with saiddistributor assembly.

6. An ignition system of the type defined by claim 5 including meansbiasing said output coupling member against movement at rotationalspeeds of said generator assembly below a predetermined speed, andwherein said output coupling member overcomes said biasing means andmoves against said biasing means at rotational speeds of said generatorassembly above said predetermined speed to move said distributorassembly relative to said generator assembly and said housing.

7. An ignition system of the type defined by claim 6 wherein said outputcoupling member includes a shaft member and wherein the shaft member isoperatively associated with a gear unit operable on rotation of theshaft in one direction to rotate said distributor assembly relative togenerator assembly and said housing in an opposite direction.

8. An ignition system of the type defined by claim 7 and furtherincluding stop means on said housing and operable to limit movement ofsaid output coupling member in response to action of said biasing meansin one direction, and to limit movement of said output coupling memberin an opposite direction in response to torque transmitted through saidfluid coupling.

References Cited UNITED STATES PATENTS 2,862,146 -11/ 1958 Kreuthmeir123-148 3,009,975 11/1961 I-Iufferd et al. 123-148 3,082,333 3/1963Hufferd et al 3108.7 3,094,108 6/1963 Small et al. 123--148 LAURENCE M.GOODRIDGE, Primary Examiner.

